too rich fuel mix?

its important to measure your mix, im not going to go into details about the the correct oil-gas ratio is because it will start a ****storm.

manufactures recommend 16:1 break in most run at most 20:1.

if there is too much oil then yes it will bog down as oil does not burn as well as gas and with a set amount of mix flowing through the carb you will have less gas and thus less power. The carb may be tuned perfectly and thus it isnt "rich" technically, but you might experience some of the same symptoms.

too much oil can lean your engine out and cook it as well..!

24:1 break in at the most. 16:1 is for sae30 motor oil, which no one (hopefully) uses.
Measure it, and NEVER just pour oil into the gas tank.

i broke my motor in on 20:1 with 2 stroke motor oil, i am now running 32:1.

I also break 'em in with 24:1 (2 gallons) & then switch to 32:1.
Don't start worrying about it running too rich until you have about 4 gallons run through the engine because it will keep running better & better the more it breaks in.

Should one ever go below a 32:1 ratio? I was thinking of going to like 40:1 because I'm slightly blowing out some oil smoke and I have over 1,000 miles on the engine so it is definitely well beyond break-in.

jmwapp said:

Should one ever go below a 32:1 ratio? I was thinking of going to like 40:1 because I'm slightly blowing out some oil smoke and I have over 1,000 miles on the engine so it is definitely well beyond break-in.

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If the oil you are using is recommended for 40:1 and you check your spark plug after a few miles to see what color it is to know if you are running a little lean on fuel or not it should be fine to go to a 40:1 mix.

it all depends on oil quality and if it is recommended by the oils maker to use it at the 40:1 ratio.

I run 100:1 Ratio in all my engines and have been for a long time, I use Opti2 which is designed to be ran at that ratio and my engine produce almost zero smoke or oil smell, and I get excellent performance, power and top speed out of my bikes running the Opti2, some will not go down that road but myself and several others on here have proven over a good long time now that with proper carb tuning that the opti2 @ 100:1 is an excellent way to go.

Echo makes a Synthetic Blend 2 stroke oil that can be picked up at any Home Depot and it's recommended mix is 50:1 I know of one member here that has been running that oil at 50:1 in his bike for a good while now and has had great results, Lucas makes a Synthetic Blend oil that some here are running with good results also, seems it is a good oil at 40:1 if I remember right, it may also work out nice at 50:1 but I'm not sure on that.

Quality oil, that is recommended at 40:1, properly tuned carb and you should have no problems from running that mix.

Map

I fully agree as well, the air fuel ratio is directly related to the fuel oil mixture so I don't worry too much about carb tuning until I'm off the high oil content in my break in mix which is 16:1 Quaker State high milage oil in the first tank, this just gets between idle and mostly no load revs with a little really easy riding on for the first hour of opereation, after that I switch to 20:1 with a good non synthetic 2 cycle oil but not worrying about tuning the carb, still taking it kinda easy on the engine and no full throttle under load bursts for about 30 to 45 minutes of run time, After this I'll add in more fuel to bring the mix up to 32:1 and finish the break in on this mix where the fuel mix is more lined up with the right air fuel ratio so I may move the needle up or down on the 32:1 mix, but after that gallon of fuel is consumed, this is where I'll switch to my Amsoil Dominator 2 cycle oil and determine if re jetting is needed or not as well as which ratio I'll finally end up using. I like to run 40:1 or even 50:1 depending on oil quality. Amsoil does make a 100:1 oil that works great but I won't mix mine at those ratios unless the oil is specifically made to run in those ratios like Opti 2 or Amsoil Saber. Amsoil's Dominator and Interceptor are both designed for a 50:1 mix and it's also not uncommon for one engine to like one and not the other while another engine built the same way likes the other better and vice versa so it's also worth it to experiment with the high performance 2 cycle oils to see what your engine likes the best.
But back on the main subject, I just tune my carb enough to keep it from running lean on fuel until I'm done with the break in mixtures, then I'll tune the carb accurately once I'm on the more fuel less oil mix as it can go rich at the higher ratios.

2door said:

Ditto to Map's post and I'll add two things. These ahev been covered many times before but it doesn't hurt to refresh even in an old thread.

When you decrease the oil content in your mix you effectively increase the fuel ratio. This will equate to a richer condition in regards to air/fuel which might show as four stroking, loss of power etc.

When a builder is running 16 or 20:1 and tunes his carb to that ratio he can expect a rich condition when he moves into the lower oil to fuel ratio, 32 or 40:1. I'm one of those guys Map mentioned who uses a 100:1 ratio. At those mixtures leaning the fuel to air mix is essential.
A 50:1 mix, if the oil is formulated for that ratio, will require you do some experimentation with jetting to get the most from your engine.

Tom

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Thank you Tom, after reading my post again I can see how it would seem I was saying less oil would make for a lean rather than rich condition, I didnt mean for it to seem this way, I just always encourage the plug checking since a lean condition is such a killer on a 2 smoker engine... thank you sir for clearing this up and making it clear how it works.

Once again I was thinking one thing and typing something that coud be easily misunderstood.....lol!

Map

Hey it happens to all of us at one time or the other...

Davezilla said:

Hey it happens to all of us at one time or the other...

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Aint that the truth brother......lol!!!!

I think it has something to do with being human... but hey.....! I could be wrong about that...!

Map

Same here Tom Opti2 100:1 start of engine for the first time and I just ride it like I plan to ride it.

I dont do 15 miles at wide open throttle right off the bat but after about 25 miles I do, not a single failure since I switched to Opti2.

Excellent lu rication is why I can do them the way I do, I wouldn't trust any other oil I have ever used to do the engines like I do.

Map

That was extremely informative guys, thanks. However, I do not see myself taking the risk of switching to Opti2 with this particular engine. (which is from www.thatsdax.com) I would be interested to give that a shot on a new motor though and I would probably do that right from the start same as 2door.

I would like to add also, from the perspective of someone who just tried this firsthand, that marine oil 2stroke oil is NOT the same as regular air-cooled 2 cycle oil. I had a couple of guys (engine mechanics and knowledgeable fellas) tell me that there is no difference between 2 stroke oils. I got the "2stroke is 2stroke" argument and due to the fact that the Castrol 2 stroke that I was using from the start was no longer available in my community, I had to switch. Well, when I started running the Valvoline 2-cycle marine oil, the engine started making a "rubbing/hissing" sound like there was less lubrication in the engine. I switched to regular valvoline 2 cycle and the symptom disappeared completely. Hmm

I'll be burning Opti2 in a Flaming Horse Silver Slant 80cc when the build is complete.

Rump Rocket said:

I'll be burning Opti2 in a Flaming Horse Silver Slant 80cc when the build is complete.

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Tune the carb right and you'll enjoy it.

Map

2door said:

There are many theories on how best to break in a Chinese 2 stroke. I'm one who starts a new engine with my Opti-2 @ 100:1 and I never change from day one. I don't baby my engines but I don't abuse them either. In fact I ride from the first start like I ride normally. I don't subscribe to the 'cool down' method. That being to ride and then stop to allow the engine to cool. I climb hills under WOT conditions, do flat ground runs at part throttle then twist in all I can, not worrying about 'taking it easy'.

I attribute my success with these little engines to using an oil that provides adequate lubrication through all phases of running and allows for good piston ring seating in the early stages.
Like I said, I don't baby them, but I don't treat them like fine porcelain either. So far, so good. I've never had one let me down or have a major failure.

With that said I will admit that I don't start playing with carburetor tuning, jet sizes, until I've burned a couple of tanks of fuel. I let them burble and run rich a little then I solder and drill my jets to give me the best performance.
But that's just me. Others have different opinions and methods that work too. It is anything but an exact science. It boils down to 'whatever works for you'.

Tom

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I use regular two stroke oil at 40:1 but aside from that detail, this is exactly how I run new engines. Been working for decades on all engine types.
I learned from a fast racer buddy to break it in like you plan to ride it and have done it ever since.